MicroRNA-21 controls the development of osteoarthritis by targeting GDF-5 in chondrocytes

Yukun Zhang,Jie Jia 생화학분자생물학회 2014 Experimental and molecular medicine Vol.46 No.-

Osteoarthritis is a common cause of functional deterioration in older adults and is an immense burden on the aging population. Altered chondrogenesis is the most important pathophysiological process involved in the development of osteoarthritis. However, the molecular mechanism underlying the regulation of chondrogenesis in patients with osteoarthritis requires further elucidation, particularly with respect to the role of microRNAs. MiR-21 expression in cartilage specimens was examined in 10 patients with knee osteoarthritis and 10 traumatic amputees. The effect of miR-21 on chondrogenesis was also investigatedin a chondrocyte cell line. The effect of miR-21 on the expression of growth differentiation factor 5 (GDF-5) was further assessed by luciferase reporter assay and western blot. We found that endogenous miR-21 is upregulated in osteoarthritis patients, and overexpression of miR-21 could attenuate the process of chondrogenesis. Furthermore, we identified GDF-5 as the direct target of miR-21 during the regulation of chondrogenesis. Our data suggest that miR-21 has an important role in the pathogenesis of osteoarthritis and is a potential therapeutic target.

Cytosolic escape of mitochondrial DNA triggers cGAS-STING-NLRP3 axis-dependent nucleus pulposus cell pyroptosis

Zhang Weifeng,Li Gaocai,Luo Rongjin,Lei Jie,Song Yu,Wang Bingjin,Ma Liang,Liao Zhiwei,Ke Wencan,Liu Hui,Hua Wenbin,Zhao Kangcheng,Feng Xiaobo,Wu Xinghuo,Zhang Yukun,Wang Kun,Yang Cao 생화학분자생물학회 2022 Experimental and molecular medicine Vol.54 No.-

Low back pain (LBP) is a major musculoskeletal disorder and the socioeconomic problem with a high prevalence that mainly involves intervertebral disc (IVD) degeneration, characterized by progressive nucleus pulposus (NP) cell death and the development of an inflammatory microenvironment in NP tissue. Excessively accumulated cytosolic DNA acts as a damage-associated molecular pattern (DAMP) that is monitored by the cGAS-STING axis to trigger the immune response in many degenerative diseases. NLRP3 inflammasome-dependent pyroptosis is a type of inflammatory programmed death that promotes a chronic inflammatory response and tissue degeneration. However, the relationship between the cGAS-STING axis and NLRP3 inflammasome-induced pyroptosis in the pathogenesis of IVD degeneration remains unclear. Here, we used magnetic resonance imaging (MRI) and histopathology to demonstrate that cGAS, STING, and NLRP3 are associated with the degree of IVD degeneration. Oxidative stress induced cGAS-STING axis activation and NLRP3 inflammasome-mediated pyroptosis in a STING-dependent manner in human NP cells. Interestingly, the canonical morphological and functional characteristics of mitochondrial permeability transition pore (mPTP) opening with the cytosolic escape of mitochondrial DNA (mtDNA) were observed in human NP cells under oxidative stress. Furthermore, the administration of a specific pharmacological inhibitor of mPTP and self-mtDNA cytosolic leakage effectively reduced NLRP3 inflammasome-mediated pyroptotic NP cell death and microenvironmental inflammation in vitro and degenerative progression in a rat disc needle puncture model. Collectively, these data highlight the critical roles of the cGAS-STING-NLRP3 axis and pyroptosis in the progression of IVD degeneration and provide promising therapeutic approaches for discogenic LBP.

Functional Analysis of Wheat TaPaO1 Gene Conferring Pollen Sterility Under Low Temperature

Changping Zhao,Guoliang Yuan,Yukun Wang,Shaohua Yuan,Peng Wang,Wenjing Duan,Jianfang Bai,Hui Sun,Na Wang,Fengting Zhang,Liping Zhang 한국식물학회 2018 Journal of Plant Biology Vol.61 No.1

Thermosensitive male sterility plays an important role in wheat fertility and production. As a key enzyme for chlorophyll degradation, pheophorbide a oxygenase (PaO) can suppress cell death in plants. We cloned the wheat gene TaPaO1 from the thermosensitive genetic male sterile (TGMS) line BS366; it encodes a typical PaO protein, containing a conserved Rieske [2Fe-2S] iron–sulphur motif, a mononuclear non-heme iron-binding motif, and a C-terminal CxxC motif. TaPaO1 was expressed in all tissues and was upregulated during the meiosis stage of BS366 anthers under low temperature. Subcellular localization of TaPaO1 specifically labelled the surrounding of chloroplasts. TaPaO1 regulated by RD29A promoter which responded to low temperature led to pollen sterility in transgenic tobacco. Expression analysis showed that TaPaO1 exhibited a higher level of expression in the anther than in other tissues in transgenic tobacco plants during low temperature treatment. We propose that the higher senescence-related activity of TaPaO1 may lead to the cell death of anthers, which happens at an early developmental stage under low temperature. These results provide new insights into the function of PaO during the early developmental stage of anthers. PaO is closely related to cell death regardless of whether it exhibits increased activity or inactive.

Photoelectrocatalytic Oxidation of Methane into Methanol Over ZnO Nanowire Arrays Decorated with Plasmonic Au Nanoparticles

Jia Liu,Yinghua Zhang,Zhian Huang,Zhiming Bai,Yukun Gao 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2019 NANO Vol.14 No.2

The pursuit for efficient conversion of methane under ambient conditions remains a challenge. Here, we reported photoelectrocatalytic oxidation of methane into methanol over ZnO nanowire arrays (NWAs) decorated with Au nanoparticles (NPs) under simulated sunlight illumination with ambient conditions. The photoelectrochemical (PEC) performances of the ZnO and ZnO/Au photoanodes were investigated to analyze the behavior and intensity of the reaction process of methane oxidation. The Faradaic efficiency of ZnO/Au was calculated to be 32.11%, nearly three times of 11.69% for ZnO. The above results show that ZnO NWAs exhibited exceptional activity as photoanode for photoelelctrocatalytic methane oxidation, and the decoration of Au NPs further enhanced the photo-activity via the surface plasmon resonance expanding its absorption spectra to visible region. On the other hand, as a co-catalyst, Au can promote the oxidation of methane by providing the trapping sites and active sites to facilitate the separation and also suppress the recombination of photogenerated charges and the existence of Au can boost the reaction by lowering the activation energy. This research demonstrates that ZnO NWAs decorated with Au NPs hold great promise for photoelectrocatalytic methane oxidation.

Influence of a Dominant Fault on the Deformation and Failure Mode of Anti-dip Layered Rock Slopes

Menglong Dong,Faming Zhang,Cheng Yu,Jingqing Lv,Huixin Zhou,Yukun Li,Yiyan Zhong 대한토목학회 2022 KSCE JOURNAL OF CIVIL ENGINEERING Vol.26 No.8

Toppling is a kind of failure mode that commonly exists in anti-dip rock slopes. Toppling deformation has a great influence on the stability of rock slopes, which often leads to geological disasters such as sliding and collapse of anti-dip slopes. However, a large number of faults and other structural planes will be produced in many rock slopes due to the action of geological structure movement. In the investigation, it is found that there are not only toppling deformation,but also faults and other geological structures in the toppling deformation rock slope. Previous studies have calculated the depth of toppling deformation, which is considered from the development characteristics of toppling deformation itself. In this paper, based on the field investigation of the anti-dip rock slope with bedding faults, the relationship between the depth of toppling deformation and the location of faults is analyzed by three-dimensional discrete element method. When the dominant structural plane and toppling fracture surface exist at the same time, the main factors affecting the failure of the reverse dip rock slope can be obtained by determining the different depths of the two planes. The final failure depth and failure mode of the toppling deformation in an anti-dip rock slope with a dominant structural plane can be preliminarily determined.

Determination of Maximum Penetration Depth of Suction Caissons in Sand

Wu Yuqi,LI Dayong,Zhang Yukun,Chen Fuquan 대한토목학회 2018 KSCE Journal of Civil Engineering Vol.22 No.8

The suction caisson is a large top-closed cylindrical steel structure in diameter, short in length and much thinner in skirt wallthickness. The total resistance of the suction caisson during installation consists of the tip resistance and the skirt wall friction. However, since the thickness of the skirt wall is very small, the skirt wall friction may produce additional vertical stress and shearstress in soil at the skirt tip level, and this additional vertical stress and shear stress will contribute to the increase in the skirt tipresistance. At the same time, seepage induced by suction also causes the tip resistance to reduce significantly. A modified slip-linefield is proposed in this study estimating the tip resistance in terms of the slip-line theory. The expression obtaining the minimumsuction to install the suction caisson is also proposed in terms of the force equilibrium. In addition, the critical suction is determinedbased on the mechanism of sand piping. Thus, the maximum penetration depth of the suction caisson can be reached when the criticalsuction equals the minimum suction. Results from calculations of the minimum suction and the maximum penetration depth havebeen proved to be in a good agreement with the measured data.

A Three-Dimensional ZnO/CdS/NiFe Layered Double Hydroxide Photoanode Coupled with a Cu2O Photocathode in a Tandem Cell for Overall Solar Water Splitting

Jia Liu,Yinghua Zhang,Zhiming Bai,Zhian Huang,Yukun Gao,Yuan Yao 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2019 NANO Vol.14 No.11

An integrated tandem photoelectrochemical (PEC) cell, composed of a three-dimensional (3D) ZnO/CdS/NiFe layered double hydroxide (LDH) core/shell/hierarchical nanowire arrays (NWAs) photoanode and a p-Cu2O photocathode, was designed for unassisted overall solar water splitting in this study. The optical and photoelectrochemical characteristics of ZnO-based photoanodes and Cu2O photocathode were investigated. The results show that ZnO/CdS/NiFe LDH nanostructures offer significantly enhanced performances with a photocurrent density reaching 5.8 mA · cm -2 at 0.9 V and an onset potential as early as 0.1 V (versus RHE). The enhancement can be attributed to the existence of CdS nanoparticles (NPs) which boosts the light absorption in visible region and enhances charge separation. Moreover, the introduction of NiFe LDH nanoplates, with unique hierarchical mesoporous architecture, promotes electrochemical reactions by providing more active sites as co-catalyst. On the above basis, the ZnO/CdS/NiFe LDH–Cu2O two-electrode tandem cell system was established. At zero bias, the device shows a photocurrent density of 0.4 mA · cm -2 along with the corresponding solar-to-hydrogen (STH) conversion efficiency reaching 0.50%. Our results indicate that the tandem PEC cells consisting of metal–oxide–semiconductor photoelectrodes based on Earth-abundant and low-cost materials hold promising application potential for overall solar water splitting.

Triptolide inhibits ovarian cancer cell invasion by repression of matrix metalloproteinase 7 and 19 and upregulation of E-cadherin

Hongxi Zhao,Zhifu Yang,Xiaohong Wang,Xianzhi Zhang,Meng Wang,Yukun Wang,Qibing Mei,Zhipeng Wang 생화학분자생물학회 2012 Experimental and molecular medicine Vol.44 No.11

Triptolide, a compound extracted from the traditional Chinese medicine preparation of Tripterygium wilfordii Hook F., has been reported to have anti-inflammatory and anti-cancer activities. However, its effect on ovarian cancer invasion is unknown. We observed that MMP7 and MMP19 expression increased in ovarian cancer tissue. Triptolide treatment inhibited the migration and invasion of ovarian cancer cells SKOV3 and A2780 at the concentration of 15 nM. We also observed that triptolide suppressed MMP7 and MMP19 promoter activity in a dose-dependent manner,down-regulating the expressions of these promoters on mRNA and protein level. Moreover, triptolide enhanced E-cadherin expression in ovarian cancer cells. In vivo, triptolide inhibited tumor formation and metastasis in nude mice, and suppressed MMP7 and MMP19 expression; it also enhanced E-cadherin expression in tumor in a dose-dependent manner. Over expression of MMP7 and MMP19, or suppression of E-cadherin expression partially abolished the inhibitory effect of triptolide on invasion of ovarian cancer cells. To summarize, triptolide significantly inhibited the migration and invasion of ovarian cancer cells by suppression of MMP7 and MMP19 and up-regulation of E-cadherin expression. This study shows that triptolide is a good candidate for the treatment of ovarian cancer and reduction of metastasis.

Experimental Studies on Shear Behavior of Sand-Suction Caisson Wall Interface under Variable Normal Load and Penetration Rate

Yifan Li,Dayong Li,Yuqi Wu,Yukun Zhang 대한토목학회 2023 KSCE Journal of Civil Engineering Vol.27 No.7

Shear characteristics of the interface between sand and the suction caisson wall play animportant role in determining the friction resistance along the suction caisson wall. In thisstudy, a variable normal load (VNL) reflecting the effects of the penetration depth andinstallation rate of a suction caisson is applied using the torsional interface shear apparatus toexamine the interface shear behavior. Results show that the interface friction coefficientdecreases with the increase of the normal stress and shearing rate until reaching a criticalvalue. When the friction coefficient reaches the critical value, the friction coefficient changeslittle with the increase of normal stress. The variation of the friction coefficient caused by theseepage flow and penetration rate should be considered for calculating the frictional forcealong the caisson wall. Given the same shearing rate, the normalized efficiency parameter ofthe interface under the VNL is higher than that obtained under the CNL. The suctioncalculated based on the test results of this study is in good agreement with that from the Tenbyproject, indicating that our findings are reliable and beneficial to analyze the installationprocess of the suction caisson.

Kinetic analysis of NO-Char reaction

Shaozeng Sun,Xidong Hu,Penghua Qiu,Juan Qian,Yukun Qin,Juwei Zhang 한국화학공학회 2009 Korean Journal of Chemical Engineering Vol.26 No.2

Two Chinese coals were used to prepare chars in a flat flame flow reactor which can simulate the temperature and gas composition of a real pulverized coal combustion environment. Acid treatment on the YB and SH chars was applied to obtain demineralized chars. Kinetic characterization of NO-char reaction was performed by isothermal thermogravimetry in the temperature range of 973-1,573 K. Presence of catalytic metal matter can increase the reactivity of chars with NO, which indicates that the catalytic effects of inherent mineral matter play a significant role in the NO-char reaction. The discrete random pore model was applied to describe the NO-char reactions and obtain the intrinsic kinetics. The model can predict the data for all the chars at various temperatures well, but underestimate the reaction rates at high carbon conversions for the raw YB and SH chars, which can be attributed to the accumulation of metal catalyst on char surface.